At present, a trunking communication system such as an LTE-based trunking communication system is widely applied to the fields of government departments, public security, emergency communications, electric power, civil aviation, petrochemical industry, armed forces, and the like. Therefore, in order to meet application demands of this trunking communication system, a system where a common service and a trunking service are concurrent (e.g., an LTE-based system where the common service and the trunking service are concurrent) emerges in the market.
At present, firstly, in a trunking communication system supporting concurrence of the common service and the trunking service (e.g., an LTE-based trunking communication system where the common service and the trunking service are concurrent), when the common service is executed, communications between user terminals have a Radio Resource Control (RRC) link, the trunking service is a half-duplex bidirectional service, a trunking user terminal is constructed to belong to a certain group of user terminals in a certain given area, in a communication process, any member in the group may become a speaker, but only one speaker, namely a calling trunking user terminal, is allowed at any time while others are listeners, namely called trunking user terminals, the calling trunking user terminal has an RRC link, and the called trunking user terminals do not have RRC links; secondly, a service concurrence situation in the trunking communication system supporting concurrence of the common service and the trunking service includes: 1, concurrent execution of the common service and a trunking listening user service, and 2, concurrent execution of the common service, a trunking speaking user service and the trunking listening user service; and finally, radio environments to which the trunking service and the common service are applied are complicated similarly, various abnormal situations such as radio link abnormality and inability to synchronize a process of switching a serving cell where a user terminal is located to a target cell to the target cell will be caused in the execution process of the common service and the trunking service. In this case, a target cell is re-selected from the serving cell where the user terminal is located and a neighbor cell thereof to initiate an RRC reestablishment process so as to recover the services. A solution must be found to solve the problem how to recover the trunking listening user service subsequently when an abnormality occurs in the LTE-based trunking communication system where the common service and the trunking service are concurrent.
The abovementioned content is merely used for assisting in understanding the technical solutions of the present document, and it is not representatively admitted that the abovementioned content is the existing technology.